Watch Black Sabbath performing Elvis’ “Blue Suede Shoes”

Back in 2004, Black Sabbath released a great box set that featured a rare recording of a performance of “Blue Suede Shoes,” a classic rock by Carl Perkins and immortalized by Elvis Presley.

The cover was recorded during rehearsals for a German TV show in the early 1970s. At the time of the release, Tony Iommi stated that the live version should never have been recorded. “That was just a test for the cameras – it was a joke, basically,” the musician told Launch Radio Networks.

Take a look:

However, the band was shocked to realize that the momentum had not only been recorded by the cameras, but was also broadcast on the television channel:

We had just started playing the song, and Ozzy [Osbourne] had no idea of the lyrics. And of course, you can imagine the shock when we saw this going for the air? We thought, ‘My God, what is this?’, Because it was not meant to be transmitted. From there we think, ‘Oh, it’s just German TV. No one’s going to see it anyway, you know? We hardly knew.

Although it was made by Carl Perkins in 1955, “Blue Suede Shoes” was immortalized in the voice of Elvis Presley. The singer even featured the track on three different occasions on television shows, and the single was a hit on the American charts.

Other artists who even recorded their own version of the track at that time were Buddy Holly and Eddie Cochran.